[joeavaerage]

Hi,
re-reading your post and you say that you are trying to end up with 0.2mm to 0.25mm between traces. That would require endmills of
0.2mm and they are too fragile especially if you are cutting 500um deep. That would be a 100% width cut, ie full width slotting which is always a challenging
toolpath but at 250% deep!

My heavy copper boards have a SOIC with 0.6mm between the IC pin pads, ergo I can use 0.5mm endmills. I am glad I do not have to go any finer than that.

You may have seen that there are companies that make these heavy copper boards. It seems that military customers are prepared to pay the premium.
They use a combination of etching, plating and isolation routing. The cost of borads of that description complete with plated through holes is about $1000US/sq foot.
One company published design rules and they specify that the minimum distance between tracks be at least 0.4mm or at least the thickness of the copper. In my
case with 0.42mm copper if I got them to make the boards they would have a minimum spacing of 0.42mm.

I think you will have to review your design requirements with regard to either copper thickness OR minimum practical spacing.

Craig

[joeavaerage]

Hi,
PCB Material World - About Us

It looks like they have sold the last of the12oz/12oz boards that I have used but they have some 11oz/11oz and some 10oz/10oz boards.
Beware the total thickness, some of these boards are meant to be glued together in a stack.

Good outfit, they had a minimum order of $50US which he was happy to bend a little for me in New Zealand but I bought two boards 18 inch x 18 inch and
he posted to Oregon where my shipping agent is for about $90US. As I say a good outfit.

Craig